【摘要】 软土区高速公路新老路基间的沉降机理是高速公路改扩建工程中需要研究的重点问题。针对软土区高速公路路基改扩建工程，开展大型模型试验，分析新老路基的沉降变形、水平位移以及路基固结特性的变化规律。结果表明：软土区扩建路基及地基的沉降趋势呈现抛物线型，新路基和拼接区域的沉降最大，不同深度的新老地基沉降趋势具有高度相似性；新老路基拼接区域坡脚处的水平位移要明显超过新路基坡脚，最大达到0.24 mm；分级加载过程中，新路基对老路基施加的侧向压缩作用要大于老路基在荷载作用下所产生的侧向变形作用；路基沉降在荷载加载的24～37小时内急剧发生，之后速度减慢趋于平缓；新老路基的差异沉降，主要是由老路基下地基土的压缩性小于新路基下地基土造成的。更多还原

【Abstract】 Settlement mechanism between new and old roadbed of highway in soft soil area is a key issue to be studied in highway reconstruction and expansion project. For the soft soil area highway roadbed reconstruction and expansion project, a large-scale model test was carried out to analyze the settlement deformation and horizontal displacement of the new and old roadbeds as well as the change rule of the roadbed consolidation characteristics. The results show that the settlement trend of the expanded roadbed and foundation in the soft soil area is parabolic, the settlement of the new roadbed and the splicing area is the largest, and the settlement trend of the new and old foundations at different depths is highly similar. The horizontal displacement at the foot of the slope in the spliced area of the new and old roadbase is significantly more than that at the foot of the slope of the new roadbase, reaching a maximum of 0.24 mm. The lateral compression exerted by the new roadbase on the old roadbase in the process of grading loading is greater than that of the lateral deformation of the old roadbase under the action of loading. The settlement of the roadbed occurred sharply within 24-37 h of loading, after which the speed slowed down and leveled off. The difference in settlement between the old and new roadbeds is mainly caused by the fact that the compressibility of the foundation soil under the old roadbed is smaller than that under the new roadbed.更多还原